Objectives: The highest levels of glomerular filtration rate are associated with increased coronary heart disease (CHD) risk, an issue we investigated in separate sexes in a population prone to metabolic syndrome.
Research Methods and Procedures: In total, 1948 participants of the Turkish Adult Risk Factor study with available creatinine determinations were studied at a mean 3.4 years’ follow-up. Using quartiles of creatinine, risk in Cox models of incident CHD or the likelihood of combined prevalent and incident CHD was assessed.
Results: Women in the lowest creatinine quartile demonstrated the lowest risk profile across diverse variables, except showing low high-density lipoprotein cholesterol and average apolipoprotein A-I and lipoprotein (a) concentrations implicating impaired atheroprotective properties. Whereas serum creatinine in men was not significantly associated with 6 proinflammatory variables comprised in linear regression analysis, apolipoprotein A-I and lipoprotein (a) were significant positive covariates in women, the latter tending to negative association in women without metabolic syndrome. In men, the highest (>1.10 mg/dL), compared with the lowest, creatinine quartile significantly predicted CHD risk, at 1.85-fold relative risks, after adjustment for established risk factors. The risk curve in women was U-shaped, the top and bottom quartiles tending to display higher risk (odds ratio, 1.28 [95% confidence interval, 0.91-1.80]) compared with the 2 intermediate quartiles.
Conclusions: Increasing serum creatinine values are associated strongly and independently with CHD risk in men but not in women in whom the risk curve is U-shaped. The phenomenon of low creatinine levels underlies some hitherto unexplained relevant observations, and low measurements may be attributed to inassayability secondary to involvement in autoimmune activation.